
Have you ever thought about why you have two nostrils? When you need to take in more air during strenuous exercise, mouth breathing becomes necessary. But breathing through your nose is much better than breathing through your mouth for various reasons. When I have had a cold or allergy and one nostril was plugged, the other still worked, at least partially. That could be the reason for two nostrils. But that’s not the whole story of why two nostrils are better than one.
It may be a surprise to you, as it was to me, that even when your nostrils are not plugged, one of them will always draw in more air than the other. They trade off every few hours. Your nostrils prepare the air for your lungs by warming it and adding moisture. When the nostril that has been passing most of the air becomes dry, the other can take over while the first one recovers moisture.
A second reason two nostrils are better than one is more efficient fragrance detection. We detect smells when odorant molecules dissolve in the nasal mucus, where they bind to neurons that send signals to the brain. Some chemicals are quickly absorbed, while others are absorbed more slowly. The nostril with faster airflow will detect odor chemicals that dissolve quickly, while the nostril with slower airflow will have time to detect slow-dissolving chemicals. The brain combines the two fragrances to give us a more complete picture of the environmental smells.
Perhaps another reason two nostrils are better than one is that they help detect the direction smells are coming from. Our ears on opposite sides of our heads can give us information about the direction of sound. Our brains combine the vision from our two eyes to give us a three-dimensional view of the world around us. Even though the nostrils are not as far apart as our ears and eyes, they can still give us a clue to determine the origin of a smell.
Your nostrils contain hairs that filter out some of the dust and pollutants in the air. That is another advantage over mouth breathing. One more thing that comes to mind is that having two nostrils allows a ridge of cartilage to form between them, giving your nose its distinctive shape. (Although you may not think that the shape of your nose is advantageous.) Overall, I have to admit that two nostrils are better than one. I am glad the Creator made that part of the body’s marvelous design.
— Roland Earnst © 2026
Reference: popsci.com









